Allow cream cheese to soften slightly by letting it set at room temperature for about 10 minutes.
Open can of chicken and drain, reserving broth to use in another recipe. (Store broth in fridge or freezer depending on how soon you'll use it.)
Drain canned corn and set aside.
Drain and rinse canned black beans and set aside.
Open can of diced green chilies.
Mix chicken, cream cheese, cumin, and diced green chilis together until thoroughly combined.
Layer four corn tortillas in the bottom of a 9X9 inch pan that has been sprayed with non-stick cooking spray. You may have to cut or tear the tortillas to cover the entire bottom of the pan.
Place 1/2 of the chicken mixture onto the layer of tortillas, gently pressing it out to evenly cover the tortillas on the bottom of the pan.
Pour 1/2 of the drained corn over the chicken mixture and distribute it evenly.
Pour 1/2 of the drained black beans over the corn and distribute them evenly.
Place another layer of four corn tortillas over the black beans, cutting and tearing as necessary to cover the entire surface.
Place the remaining chicken mixture onto the layer of tortillas, gently pressing it out to evenly cover the tortillas.
Pour the remaining drained corn over the chicken mixture and distribute it evenly.
Pour the remaining drained black beans over the corn and distribute them evenly.
Cover the bean layer with the last four corn tortillas, once again, tearing or cutting to cover the entire surface.
Mix sour cream with diced tomatoes with green chilies.
Pour the can of diced tomatoes with green chilies over the top of the casserole gently spreading it to cover the entire surface.
Cover the top with one cup of shredded cheese. (We used Jack, but Cheddar will work, too.)
Bake at 350 degrees for 30 to 45 minutes until cheese is melted and casserole is heated all the way through.
Allow to set for five to ten minutes, so it's easier to get whole pieces out when serving.
Serve topped with your favorite taco toppings--lettuce, tomato, sour cream, guacamole, green onions, olives, etc.